Electrochemical Behavior of a Ni Chlorocomplex in a Lewis Basic Ionic Liquid Containing Chloride Ion

The electrochemical behavior of a chlorocomplex of nickel (Ni) was investigated in a Lewis basic and hydrophobic ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing Cl – . NiCl 2 dissolved in BMPTFSA with addition of 0.5 M BMPCl. The dissolved species of Ni(II) in BMPTFSA was identified as [NiCl 4 ] 2– by UV-visible spectrometry and magnetic susceptibility balance. The cathodic and anodic currents assignable to deposition and dissolution of Ni, respectively, were observed in cyclic voltammetry. The granular deposits of Ni were obtained on a glassy carbon electrode at 25 and 100 °C. Ni nanoparticles were dispersed in the electrolyte by galvanostatic cathodic reduction. The initial stage of Ni deposition was found to be regarded as instantaneous. The diffusion coefficient of [NiCl 4 ] 2– was calculated to be 6.6 × 10 –8 cm 2 s –1 .